Fine grain high speed photographic processing monobath composition

ABSTRACT

An improved combined developer-fixer photographic processing monobath composition and method for use thereof, providing rapid and even development while maintaining fine grain structure and producing good image quality and extended processing life, including at least in excess of 100 grams of anhydrous sodium sulphite per liter of solvent in the working monobath solution. The developer may be a combination of two developing agents and a cationic surface-active agent may be added.

[ June 25, 1974 O United States Patent [191 Speers FINE GRAIN HIGH SPEED PHOTOGRAPIIIC PROCESSING MONOBATH COMPOSITION [75] Inventor: Daniel Earle Speers, Southport,

' Conn.

[73] Assignee: General Film Development Corporation, Southport, Conn.

[22] Filed: Mar. 10, 1972 [21] Appl. No.: 233,787

[52] US. Cl 96/61 M, 96/66 R [51] Int. Cl G03c'5/38, G03c 5/30 [58] Field of Search 96/61 M, 66

[56] References Cited UNITED STATES PATENTS 3,017,270 l/l962 Tregillus et al. 96/61 M 3,240,603 3/1966 Schuler 96/66 R 3,345,166 10/1967 Land et al... 96/61 M 3,490,905 l/l970 Blake 96/66 R 3,7I5,2l4 2/l 973 Kane 96/61 M FOREIGN PATENTS OR APPLICATIONS 776,082 6/1957 Great Britain 96/61 M OTHER PUBLICATIONS British Journal of Photography, Jan. 27, 1961, pp. 38-41, 49 by Crawley.

Monobath Manual, I-Iuist, 1966, pp. 19-44, 46-47.

Primary ExaminerNorman G. Torchin Assistant ExaminerM. F. Kelley Attorney, Agent, or Firm-Bryan, Parrnelee, Johnson & Boliinger [57] ABSTRACT An improved combined developer-fixer photographic processing monobath composition and method for use thereof, providing rapid and even development while maintaining fine grain structure and producing good image quality and extended processing life, including at least in excess of 100 grams of anhydrous sodium sulphite per liter of solvent in the working'monobath solution. The developer may be a combination of two developing agents and a cationic surface-active agent may be added.

4 Claims, No Drawings BACKGROUND OF THE INVENTION 1. Field of the Invention I I This invention relates to combined developer-fixer photographic processing compositions, commonly known as monobaths, for black and white or monochrome silver halide emulsion films, and more particularly, to a fine grain, high speed developer-fixer monobath.

A monobath is a photographic processing solution which accomplishes the developmentprocess of reducing silver halide to metallic silver, as well as the fixing process of rendering remaining silver salts water soluble by combination with certain chemical compounds, all in a single solution. Monobaths generally contain a solvent, usually water, a developing agent, a preservative, alkali for activation or acceleration, a restrainer or anti-foggant and a fixing agent. Special purpose compounds have been added and the type of and amount of constituents have differed depending on the end use to which the bath is put. The monobath of this invention is intended for normal photographic processing of silver halide emulsion films.

2. Description of the Prior Art A monobath formulation desirably maintains full emulsion speed, normal contrast .and image density, normal graininess and a low fog level while providing a reasonably short time of processing. Usually, development to a fixed gamma proceeds to completion at a set rate at the same time fixation proceeds. Therefore, the developing action must be rapid enough to overcome the concurrent fixation process while the concentration of fixing agent must be high enough to insure complete clearing of the films unexposed silver halide.

Commercially available monobaths have obtained rapid processing time largely by compromising other desirable properties. Prior art monobaths controlling er-fixer monobaths of this invention maintain their activity for an unusually long time.

SUMMARY OF THE INVENTION The present invention provides an improved combined developer-fixer monobath photographic processing composition having a rapid and even development I rate while producing good image quality and maintainthe course of development by the addition of caustic alkali used to accelerate the activity of the developing agent have produced highly active, high speed developers which act at the expense of grain. Thus, fast action has been accompanied by undesirable side effects such as unacceptable image graininess or emulsion softening and in the conventional acceptable monobath, the terms high speed and fine. grain have heretofore been a contradiction in terms. Further disadvantages of prior art monobaths include an undesirably rapid chemical degradation of the solution and curtailment of the effect of and processing life of the used monobath. Monobaths seeking to overcome the aforementioned problems and shortcomings have largely been limited to special purposes and have a high specificity of bath for single film or photographic process. A comprehensive discussion of monobaths is presented in Monobath Manual, Grant Haist, Morgan & Morgan, Inc., Hastings on Hudson, New York (1966).

The monobaths of this invention exhibit a rapid rate of development activity whileat the same time maintaining a relatively fineigrain structure, high contrast, and no loss in film speed or other sacrifice or compromise of desired image quality.xMoreover, the developing fine grain structure as well as an extended life of activity by including in the monobath at least in excess of 100 grams of anhydrous sodium sulphite per 1 liter of water in the working solution. The further addition of a cationic surface-active agent is beneficial and the developer is preferably a combination of two developing agents.

Therefore, it is an object of this invention to provide a monobath composition which will enable photographic processing at a rapid rate while maintaining a fine grain structure.

An additional object is the provision of a monobath composition which will maintain its activity over an extended period of time.

A further object of this invention is to provide a monobath composition which exhibits rapid and even development free of fog, with no loss in film speed,

'while maintaining high contrast and fine grain struc- DESCRIPTION OF THE PREFERRED EMBODIMENTS The photographic processing behavior of a monobath composition is less a function of the individual components and more a function of the total composition of the solution. Since composition plays the dominant role, improved characteristics and behavior of individual monobath constituents and proportionate amounts are demonstrated in combination in the solution as a whole.

The developing agent used in the monobath of this invention is selected from a group of aromatic compounds having either two amine (NH groups or two hydroxy (OH) groups, or one amino and one hydroxy group. However, meta compounds have no developing action while ortho and para compounds show the required developing activity. The hydrogen atoms of the ment action is even and appropriately selective; thus providing an image free of fogThe combineddevelopamino group can be replaced by alkyl groups, however, no such substitution can be made for those in the hydroxy group, although the hydrogen atoms of the benzene nucleus can be replaced by further OH or NH groups. The substitution of alkyl or halogen groups for the hydrogen atoms of the benzene nucleus can increase the developing power of the compound.

The preferred developer for the monobath compositions of the present invention is a combination of 20 to 26 grams 1,4-dihydroxy-benzene (obtainable commercially under the name Hydroquinone) per 1,000milliliters water and 2.8 to 5.6 grams l-phenyl-3- pyrazolidone (obtainable commercially under the name Phenidone) per 1,000 milliliters water. 1,4- .dihydroxy-benzene by itself is a slow developer although when combined with caustic alkali its action is extremely rapid and high contrast is obtained. The developing agent l-phenyl-3-pyrazolidone alone is a fast but soft working developer. When the two developing agents are used together, a superadditive effect is obtained so that the sum of their combined actions is greater than the sum of their actions when used alone, yielding a very rapid, high contrast, fine grain, some what soft. working developer. Another developer combination is that of l-hydroxyA-methyl aminobenzene (obtainable commercially under the name Metol) with 1 ,4-dihydroxy-benzene.

Oxidation products of the developing agents formed during reduction of the silver halide can both accelerate and retard the developing process depending upon their character. Moreover, these oxidation products decompose to colored components which can stain the gelatin emulsion. Anhydrous sodium sulphite has been known as a preservative for developers by preventing the oxidation thereof as well as avoiding formation and harmful effects of the decomposition products of the oxidation products. In the monobath composition of the present invention the sodium sulphite content in the working monobath is such that it approximates 100 grams or more of the anhydrous salt in one liter of water in the working solution. In this amount sodium sulphite is also a silver halide solvent and the amount added has been found to have considerable influence on the graininess of the silver image. Although the sodium sulphite solution is alkaline, potassium or sodium hydroxide is added in an amount chosen to be sufficient to insure desired speed of development yet low enough to prevent over-development or enlarged grain structure. The preferred amount of caustic alkali is to per cent of combined developer weight.

Rapid and even development is obtained by incorporating in the monobath composition wetting agents selected from the group consisting of laurylpyridinium-ptoluene sulphonate, laurylpyridinium chloride, cetyltrimethylammonium bromide, cetylpyridinium bromide, betaphenylethylalphapicolinium bromide and dimethylbenzyllaurylammonium chloride. Although I do not wish to be bound by my theory, I believe that the charge barrier of the silver halide grain is neutralized by the foregoing cationic surface-active agents of the quaternary type which have no developing action but which by their strongly electro-active positive charge better enable the developing agent to act on the silver halide grains. The preferred amount to be added either singularly or in combination is in the range of 0.05 to 1.5 per cent of the total volume of working monobath solution.

The gamma value is generally fixed by the composition of any monobath and can be changed by varying the content of fixing agent, such as sodium thiosulphate, while the development activity is controlled by the alkali content. With the gradation and maximum density fixed, the development of film is often accompanied by a loss of film speed, however, the formulation of the instant invention yields maximum contrast with little or no loss in film speed. The range of fixing agent is 100 to 250 grams sodium thiosulphate per 1,000 milliliters water with the preferred composition containing between 220 to 250 grams of the salt. Other known fixing agents such as ammonium or potassium thiosulphate or ammonium, potassium or sodium thiocyanate may be substituted as long as the quantities chosen are sufficient to equal the relative activity of the sodium thiosulphate. The percent fixer based on total developer weight is 800 1,000 percent. To maintain selective action of the developer on the exposed silver halide and provide an image free of fog a quantity of potassium bromide or iodide or benzotriazole may be added as an antifoggant and restrainer. The preferred amount of potassium bromide to be added is in the range of 2.8 to 8.2 per cent of the combined weight of the developer.

The following examples illustrate the preparation of specific embodiments of the compositions of this invention and show the effectiveness of the invention in the processing of silver halide emulsion films.

Example l Material Amount Water lOOOrnl Anhydrous Sodium Sulphite 107g Hydroquinone 25g Potassium Bromide 1.5g Sodium Hydroxide 5.6g Sodium Thiosulphate 233g Cetylpyridinium Bromide 0.05% of total volume 8 Laurylpyridiniump t0luenesulpho- 0.15% of total volume nate The monobath compositions set forth in Examples 1 and 2 are those preferred for obtaining rapid even development and fine grain structure. The compositions as set out in the examples are of working strength solutions and may be used by bringing in contact with silver halide emulsion films for a processing time of from 2.5 to 6 minutes depending upon film type and emulsion thickness. Processing temperature is 25 C. However, higher temperatures may be used and will reduce the development time. At relatively high temperatures, for example above 105 F, modifications to the compositions may be required. The capacity of the combined developer-fixer monobath compositions of this invention equaled 2.5 to 3.5 ounces of solution per 80 square inches of film surface. Up to five rolls of film can be processed consecutively in 16 ounces of solution without serious slowing, loss of film speed or loss of quality. Film types which may be processed in the monobath compositions of this invention include those available cording to this invention. A method of photographic processing of silver halide emulsion film using this improved monobath has been provided.

I claim:

l. A high speed, fine grain combined developer-fixer aqueous monobath solution for photographic processing of silver halide films comprising the developer l,4- dihydroxy-benzene and a developer selected from the group consisting of l-hydroxy-4-methyl aminobenzene and l-phenyl-3-pyrazolidone, a fixer selected from the group consisting of thiocyanate and thiosulphate salts of compounds selected from the group consisting of ammonium, potassium and sodium, anhydrous sodium sulphite in excess of 100 grams per 1,000 milliliters of solvent in a working strength solution of monobath and a cationic surface-active agent of the quaternary type.

2. A high speed, fine grain combined developer-fixer aqueous monobath solution for photographic processing of silver halide films having a formulation comprising relative proportions of constituents as follows:

a developer selected from the group consisting of to 26 grams l,4-dihydroxybenzene, or combinations thereof with a developer selected from the group consisting of l-hydroxy-4-methyl aminobenzene and 2.8 5.6 grams l-phenyl-3-pyrazolidone, 20-25 percent total developer weight caustic alkali accelerator, 2.8-8.2 percent total developer weight potassium halide restrainer, 800l,000 percent total developer weight fixer selected from the group consisting of thiocyanate and thiosulphate salts of compounds selected from the group consisting of ammonium, potassium and sodium anhydrous sodium sulphite in excess of grams per 1,000 milliliters of solvent in a working strength solution of monobath and 0.05l.5 percent of total volume of working solution cationic surface-active agent inthe quaternary type.

3. A high speed, fine grain combined developer-fixer aqueous monobath solution for photographic processing of silver halide films as claimed in claim 2 wherein the developer is 20 to 26 grams l,4-dihydroxybenzene and 2.8 to 5.6 grams l-phenyl-3-pyrazolidene, per 1000 milliliters water.

4. A high speed, fine grain combined developer-fixer aqueous monobath solution for photographic processing of silver halide films as claimed in claim 3, wherein the surface-active agent is a wetting agent selected from the group consisting of laurylpyridinium-ptoluene sulphonate, laurylpyridinium chloride, cetyltrimethylammonium bromide, cetylpyridinium bromide, betaphenylethylalphapicolinium bromide, and

dimethylbenzyllaurylammonium chloride. 

2. A high speed, fine grain combined developer-fixer aqueous monobath solution for photographic processing of silver halide films having a formulation comprising relative proportions of constituents as follows: a developer selected from the group consisting of 20 to 26 grams 1,4-dihydroxybenzene, or combinations thereof with a developer selected from the group consisting of 1-hydroxy-4-methyl aminobenzene and 2.8 - 5.6 grams 1-phenyl-3-pyrazolidone, 20-25 percent total developer weight caustic alkali accelerator, 2.8-8.2 percent total developer weight potassium halide restrainer, 800-1,000 percent total developer weight fixer selected from the group consisting of thiocyanate and thiosulphate salts of compounds selected frOm the group consisting of ammonium, potassium and sodium anhydrous sodium sulphite in excess of 100 grams per 1,000 milliliters of solvent in a working strength solution of monobath and 0.05-1.5 percent of total volume of working solution cationic surface-active agent in the quaternary type.
 3. A high speed, fine grain combined developer-fixer aqueous monobath solution for photographic processing of silver halide films as claimed in claim 2 wherein the developer is 20 to 26 grams 1,4-dihydroxybenzene and 2.8 to 5.6 grams 1-phenyl-3-pyrazolidene, per 1000 milliliters water.
 4. A high speed, fine grain combined developer-fixer aqueous monobath solution for photographic processing of silver halide films as claimed in claim 3, wherein the surface-active agent is a wetting agent selected from the group consisting of laurylpyridinium-p-toluene sulphonate, laurylpyridinium chloride, cetyltrimethylammonium bromide, cetylpyridinium bromide, betaphenylethylalphapicolinium bromide, and dimethylbenzyllaurylammonium chloride. 